Impregnating and insulating material



Patented Jan. 7, 1941 umrap STATES 2,227,637 mnmmme AND INSULATING MATERIAL Rudolf Engelllardt, Leverkusen-I. G. weir, Germany, assignmto I. G. Farbenindustrie Aktien gesellschaft, Frankfort-on-the -Main,

No Drawing. Application may 24, 1939, Serial No.275,467. InGermany December 17, 1936 3Claims- (01.2 6042) The present invention relates to a new composition of matter suitable for being employed for insulating purposes and for filling interstices, for embedding or covering objects, such uses being referred to in the following as potting or compounding purposes.

The wax-like chlorinated naphthalenes (i. e. those of an average chlorine content between about 58% and about 60%) and the resin-like chlorinated diphenyls (chlorine content between about 60 and 62%) which are often employed for such purpows, for instance, in the preparation of cables or condensers, suilfer from the disadvantage of a. relatively low dropping or softening point. In consequence thereof, cables. condensers, transi'ormators and the like containing such materials show an insufllcient stability towards heat. It is the object of the present invention to do away with these disadvantages and to prepare a composition which is' suitable for the purposes indicated above and keeps its shape even on a prolonged exposure to a temperature of about 100 C.

With these and other objects in view my invention consists in the composition comprising a preponderant amount of a wax-like chlorinated naphthalene or a resin-like chlorinated diphenyl and a smaller amount of polyvinylcarbazole. In general. the latter is present in the mixture in an amount oi. not more than about 7.5 per cent of the whole mixture. This figure represents the upper limit within which the polyvinylcarbazole can be incorporated within the said chlorinated material by mere melting and which is permissible without impairing the characteristic properties of such chlorinated materials or preventing their use for the purposes mentioned above. On the other hand, the incorporation within such chlorinated materials of polyvinylcarbazole (within the range defined above) enects a considerable rise of the flow or dropping point of such materials thus renderlng the same more lit for the purposes for which they are intended. For giving an example, chlorinated naphthalenes of the character described can be employed as .compounding agents in condensers for motor vehicles; in case they are arranged near the engine they are often exposed to a high temperature, so that the raising of the dropping point of such compounding agents forms a grave problem in the motor-car industry. On the other hand, chlorinated diphenyls are em-' played for impregnating fabrics for cables in order to increase their flre-proofness. In this case arise of the softening point is desirable in order to prevent the impregnating materials from flowing away at a relatively low temperature.

' The effect which is achieved by my present nvention is illustrated by the following iigurcs:

A. wax-like chlorinated naphthalene of an average chlorine content of about 60% shows a considerable flow at 100 0.: upon the incorporation 6 therewith of about 1.5% of polyvinyl carbazole this product keeps its shape even after a several months heating to 100 (2.; the amount of polyvinylcarbazole to be incorporated within the material can be increased up to about 7.5%, 10 whereas in case of higher proportions of polyvinylcarbazole the capability of the product of being molten goes lost. A resin-like chlorinated diphenyl of an average chlorine content of about 62% has a flow point of 40, whereas the incorporation therewith of about 7.5% of polyvinylcarbazole effects a rise of the how point to 70 0.; a similar effect is tobe observed in case lower amounts of polyvinyljcarbazole are incorporated therewith. The effect involved by the present invention is contrary to all expectations as the soft- .ening point of such materials is generally reduced in case additional substances are incorporated therewith.

As to the preparation of polyvinylcarbazole which is employed in the present invention I refer to U. S. Patent No. 2,072,465 to Reppe et al. I am aware of the fact that it is propomd therein to employ chlorinated polynuclear aromatic hydrocarbons such as chlorinated naphthalene and chlorinated diphenyl as softeners for polyvinylcarbazole. Such compositions are proposed therein for use as artificial leather, toils for condensers and the like. The term "softeners" indicates that the chlorinated polynuclear aromatic hydrocarbons are employed in a minor proportion when compared with the polyvinylcarbazole, whereas according to the present invention the upper limit of the polyvinylcarbazole is about 7.5%. The compositions of the said U. 8. Patent No. 2,072,465 represent thermoplastic'materials. which are not capable of being molten, whereas the compositions of this invention show the typical properties of chlorinated naphthalenes or chlorinated .diphenyls andrcan be employed for impregnating potting or compounding p rposes.

This application is a continuation-in-part applicat'ion of my prior application. Serial No. 178,659, flied December 8, 1937. r

1. The composition of. matter comprising achlorinated polynuclear aromatic hydrocarbon selected from the group consistingof chlorinated diphenyls and chlorinated naphthalenes, the said materials having homogeneously incorporated therewith a polymerized N-vlnylcarbazole in an 3. A composition 0'2 matter comprising a reinamolmt of not more than about 7.5% of the total like chlorinated diphenyi of an average chlorine mixture: 7 content or about 62%-and about 7.5% 01 poly- I 2. A composition of matter comprising .a waxvinylcarbazole.

like chlorinated naphthalene of an average RUDOLF' ENGELHARD'I. 5

chlorine content of about 60% and about 7.5% of poiyvinyicarbazole. 

